This invention relates generally to oxygen concentration, and more particularly to apparatus and methods for employing magnetism for air stream oxygen concentration.
Air is commonly used as a source of oxygen (21% mol percent of dry air). Many uses of oxygen can benefit from an enriched composition. In combustion processes, the 79% non-oxygen content can represent either a contaminant, or a carrier of a contaminant, in the exhaust products. When it is to be used in its near pure state, oxygen must be separated from air, which conventionally requires a considerable expenditure of power. The enhancement of the oxygen content in air by only modest amounts can result in benefits to many oxygen-using processes, either in power reduction and/or air pollution reductions.
Most gases are diamagnetic; that is, they tend to be repelled from a magnetic field. Only a very few gases are paramagnetic and tend to be attracted into or toward a magnetic field, and of these, oxygen is the only common gas. It is a very important circumstance that the magnitude of the magnetic susceptibility of oxygen is many times greater than that of any other common gas. As an example, the volume magnetic susceptibility of oxygen at standard conditions, 142×10−9 cgs, may be compared with that of nitrogen, −0.40×10−9 cgs.
Recent developments in large high field magnets (particularly of the superconducting type) have made it feasible to create a very intense magnetic field at a modest cost and very low operating costs. There is need to adapt such magnets to oxygen separation.